Stabilized nap fabric



United States Patent 3,1275% STABILIZED NAP FABRIC Julian J. Hirshfeid, Decatur, Ala, assignor, by mesne assignments, to Monsanto Chemical Company, a corporation of Delaware No Drawing. Filed Nov. 27, 1961, filer. No. 155,171 9 Claims. (Cl. 161-64) This invention is concerned with the treatment of the raised surface of Woven, non-woven and knitted synthetic fabrics to prevent distortion of the raised surface due to normal wearing and laundering conditions. More specifically, this invention is concerned with preventing the matting, shedding and pilling of the nap of acrylic fabrics after subjecting these fabrics to normal laundering and wearing conditions, as well as preserving a soft hand.

In the past the raised surfaces of fabrics composed of synthetic fibers have been stabilized by the use of salts which were corrosive; therefore, special and expensive production equipment was necessary to apply these salts, usually as a solution, to the raised surface of the fabrics. Some of the salts were the pure metal halides, such as zinc chloride, lithium bromide and water soluble thiocyanates. These salts were very corrosive to the standard finishing mill equipment. In addition, these salts gave a harsh hand which was very undesirable and affected the color to such an extent that the fabric was unacceptable. While the harsh or crisp hand could be softened, this entailed additional chemical treatment and equipment which added to the cost of the fabric.

An object of this invention is to provide a method by which the nap or raised surface of synthetic fabrics are stabilized under normal laundering conditions.

Another object of this invention is to provide a stabilizing agent to prevent excess pilling and shedding of the nap or raised surface of synthetic fabrics.

Another object of this invention is to provide a stabilizing agent for the nap or raised surface of synthetic fabrics which gives a soft hand.

Another object of this invention is to provide a stabiliz ing agent for the nap or raised surface of synthetic fabrics which does not deleteriously affect the color.

Another object of this invention is to provide a stabilizing agent for the nap or raised surface of acrylic fabrics which render same free of excessive pilling and shedding under normal laundering and wearing conditions.

Another object of this invention is to provide permanent stability in high pile fabrics against matting, pilling and shedding.

Other objects and advantages of this invention will become apparent from the hereinafter detailed description.

The objects of this invention are generally accomplished by applying an aqueous solution of aniline or an inorganic salt of aniline to the nap or raised surface of synthetic fabrics either woven, non-woven or knitted. Aniline is applied by the conventional padding or spraying method. While the use of the above identified stabilizin agent is the inventive concept of this specification, other agents may be used in conjunction with the stabilizing agent to impart other desirable properties to the fabrics. Some agents such as Aston 108, which is a polyarnine resin such as diethylenetriamine crossed linked with polyethylene glycol diiodide or an epoxy resin, more fully described in US. Patent 2,982,751, which is an anti-static agent may be used in conjunction with the stabilizing agent of this invention as well as a Water repellent agent such as Phobotex, F.T.C., a melamine derivative, which will not affect the hand or color, but will give excellent resistance to water penetration and absorption. These and other additives for specific end uses may be used in conjunction with the agents of this ice invention without affecting the hand and color of the fabrics.

More specifically, the synthetic fabrics were napped and then treated with an aqueous solution of aniline in the range of 0.05 percent solution to a 50 percent solution with the preferred solution being a 0.5 percent to a 2.0 percent solution. The aniline is first dissolved in an organic alcohol such as ethanol, methanol, butanol, propanol, etc, and then dissolved in water. The alcohol aids in dissolving the aniline. This dissolving in alcohol permits a more even and thorough distribution of the stabilizing agent over the surface of the trapped fabric. If the salts of aniline, such as aniline acetate, aniline hydrochloride and aniline sulfate are used then there is no need for the alcohol as these salts are completely soluble in water. There is no minimum or maximum amount of alcohol used, only what is commercially economical. Of course some must be present to dissolve the aniline. In addition other agents as defined hereinbefore may be added in conjunction with the stabilizing agents of this invention. For example water repellent agents, anti-static agents etc., may be added to the original padding bath which would result in not only stabilizing the napped or raised surfaces of the fabrics, but render them water proof, permanently anti-static and other end uses of whatever agents may be used without affecting the stabilizing of the raised surface and the color of the fabrics so treated. The napped and treated fabrics were then heated in a conventional fabric drying apparatus, such as a chain dryer or oven to evaporate the water and set or cure the stabilizing compounds. This curing results in concentrating the stabilizing agent at the intersections of the fibers in the nap to form a durable bond between and among themselves. The period of time the fabrics were heated varied from v5 minutes to 60 minutes, with the preferred time being 20 minutes, at a temperature of from 240 F. to 300' F. with the preferred temperature being 280 F. If an aqueous solution of the stabilizing compound is used alone, then the exact temperature is immaterial as long as the fabrics so treated are dried; however, the temperature must not go to the degradation point of the acrylic fibers, 350 F. The napped fabrics were then withdrawn from the drying apparatus, and it was found that the hand was of acceptable softness and the color was unaffected. The stabilizing compound and other agents, if used, were added onto the nap by the conventional padding method and spraying method which is well known in the textile field.

While this application has been generally directed to synthetic fabrics, it is especially useful in the stabilizing of the nap or raised surface of fabrics made from fibers of acrylic polymers. The polymeric materials, which may be employed in the practice of the present invention, are polyacrylonitrile, copolymers, including binary and ternary polymers containing at least percent by weight of acrylonitrile in the polymer molecule, or blend comprising polyacrylonitrile or copolymers comprising acylonitrile with from 2 to 50 percent of another polymeric material, the blend having an overall polymerized acrylonitrile content of at least 80 percent by Weight. While the preferred polymers employed in the instant invention are those containing at least 80 percent of acrylonitrile, generally recognized as the fiber-forming acrylonitrile polymers, it will be understood that the invention is likewise applicable to polymers containing less than 80 percent acrylonitrile. The acrylonitrile polymers containing less than 80 percent acrylonitrile are useful in forming films, coating compositions, molding operation, and lacquers.

For example, the polymer may be a copolymer of from 80 to 98 percent acrylonitrile and from 2 to 20 percent of another monomer containing the C=C linkage and copolymerizable with acrylonitrile. Suitable monoolefinic monomers include acrylic, alpha-chloroacrylic and methacrylic acids; the acrylates such as methylmethacrylate, ethylmethacrylate, butylmethacrylate, methoxymethyl methacrylate, beta-chloroetnyl methacrylate, and the corresponding esters of acrylic and alphachloroacrylic acids; vinyl chloride, vinyl fluoride, vinyl bromide, vinylidene chloride, l-chlro-l-bromo-ethylene; methacrylonitrile; acrylamide and methacrylamide; alphachloroacrylamide; or monoalkyl substitution products thereof; methyl vinyl ketone, vinyl carboxylates, such as vinyl acetate, vinyl chloroacetate, vinyl propionate, and vinyl stearate; N-vinylimides, such as N-vinylphthalimide and N-vinylsuccinimide; methylene malonic esters; itaconic acid and itaconic esters; N-vinylcarbazole; vinyl furane; alkyl vinyl esters; vinyl sulfonic acid; ethylene alpha, beta-dicarboxylic acids or their anhydrides or derivatives, such as diethylcitraconate, diethylmesaconate, styrene, vinyl naphthalene; vinyl-substituted tertiary heterocyclic amines, such as the vinylpyridines and alkylsubstituted vinylpyridines, for example, 2-vinylpyridine, 4-vinylpyridine, Z-methyl-S-vinylpyridine, etc.; l-vinylimidazole and alkyl-substituted l-vinylimidazoles, such as 2-, 4-, or S-methyl-l-vinylimidazo1e, and other C C containing polymerizable materials.

The polymer may be a ternary or higher interpolymer, for example, products obtained by the interpolymerization of acrylonitrile and two or more of any of the monomers, other than acrylonitrile, enumerated above. More specifically, and preferably the ternary polymer comprises acrylonitrile, methacrylonitrile, and 2-vinylpyridine. The ternary polymers preferably contain from 80 to 98 percent of acrylonitrile, from 1 to percent of a vinyl-pyridine or a l-vinylimidazole, and from 1 to 18 percent of another substance such as methacrylonitrile or vinyl chloride.

The polymer may also be a blend of a polyacrylonitrile or of a binary interpolymer of from 80 to 99 percent acrylonitrile and from 1 to 20 percent of at least one other C=C containing substance with from 2 to 50 percent of the weight of the blend of a coplymer of from 10 to 70 percent of acrylonitrile and from 30 to 90 percent of at least one other C=C containing polymerizable monomer. Preferably, when the polymeric material comprises a blend, it will be a blend of a copolymer of 90 to 98 percent acrylonitrile and from 2 to 10 percent of another mono-olefinic monomer, such as vinyl acetate, which is not receptive to dyestuff, with a sufiicient amount of a copolymer of from 10 to 70 percent of acrylonitrile and from 30 to '90 percent of a vinyl-substituted tertiary heterocyclic amine, such as vinyl pyridine or l-vinylimidazole, to give a dyeable blend having an overall vinyl-substituted tertiary heterocyclic amine content of from 2 to 10 percent, based on the weight of the blend.

The following examples are cited to illustrate the invention. They are not intended to limit it in any way. Unless otherwise noted, percentages as expressed in the examples indicate percent by weight.

Example 1 A swatch of napped fabric composed of fibers of 94 percent acrylonitrile and 6 percent vinyl acetate was padded with a 1 percent aqueous solution of aniline dissolved in methanol. The swatch was then placed in a drying oven and heated for 10 minutes at 280 F. It was then removed and allowed to cool, after which the swatch was laundered five consecutive times under normal laundering conditions and dried. There was no appreciable change in the soft hand which would affect its commercial acceptability and the color remained unchanged. In addition there was no excessive amount of matting, pilling or shedding.

Example 2 The exact method of Example 1 was followed except 4- a 3 percent aqueous solution of aniline dissolved in methanol was used. The results after the washings were the same.

Example 3 The exact method of Example 1 was repeated except a 6 percent aqueous solution of aniline dissolved in methanol was used. The results after the washings were the same.

Example 4 A swatch of napped fabric composed of 94 percent acrylonitrile and '6 percent vinyl acetate was padded with a 2 percent aqueous solution of aniline hydrochloride. The swatch was then placed in a drying oven and heated for 10 minutes at 280 F. It was then removed and allowed to cool, after which the swatch was laundered five consecutive times under normal laundering conditions and dried. There was no appreciable change in the soft hand which would affect its commercial acceptability and the color remained unchanged. In addition, there was no excessive amount of matting, pilling or shedding.

Example 5 A swatch of napped fabric composed of fibers of 94 percent acrylonitrile and 6 percent vinyl acetate was padded, at -80 percent wet pick up, with a 1 percent aqueous solution of aniline dissolved in twice its amount of methanol and 0.5 percent zinc nitrate as a catalyst. The swatch was then placed in a drying oven and heated for 15 minutes at 220 F. and then the temperature was raised to 280 F. and held there for 10 minutes. The swatch had a very soft and pleasant hand which resisted ten consecutive launderings under normal laundering conditions. No pilling, matting or shedding was observed on the washed swatch.

Example 6 A swatch of napped fabric composed of fibers of 94 percent acrylonitrile and 6 percent vinyl acetate was padded with a 2 percent aqueous solution of aniline in methanol and 1 percent Nalcsay 1050 which is a colloidal silica in water. The swatch was then placed in a drying oven and heated for 15 minutes at 220 F. for drying and then cured by heating for 10 minutes at 280 F. It was then removed and allowed to cool, after which the swatch was laundered for five consecutive times under normal laundering conditions and dried. The hand remained soft and the color was unchanged. In addition, there was no excessive amount of matting, pilling or shedding.

With the stabilizing compounds of this invention, it is possible to treat napped fabrics composed of acrylic fibers so that they may be laundered many times and their hand, color and physical properties, such as matting, pilling and shedding will not be appreciably changed from their original conditions after their washings and drying.

It is to be understood that changes and variations may be made in the invention by a person skilled in the art without departing from the spirit and scope thereof as defined in the appended claims.

I claim:

1. An article composed of the napped fabric of fibers of synthetic linear acrylonitrile and a stabilizing agent selected from the group consisting of aniline, aniline hydrochloride, aniline sulfate, aniline acetate and aniline hydrobromide.

2. The article of claim 1 in which the fabric is composed of fibers of at least percent acrylonitrile and up to 20 percent of another copolymerizable monoolefinic monomer.

3. The article of claim 2 in which the fabric is composed of fibers of 94 percent acrylonitrile and 6 percent of vinyl acetate.

4. The article of claim 2 in which the fabric is composed of fibers of ablend of 88 percent of one copolymer 5 of 94 percent acrylonitrile and 6 percent vinyl acetate 7. The article of claim 3 in which the stabilizing agent and 12 percent of another copolymer of 50 percent is aniline acetate. acrylonitrile and 50 percent methyl vinyl pyridine. 8. The article of claim 3 in which the stabilizing agent 5. The article of claim 3 in Which the stabilizing agent is aniline Sulfateis anihne 5 9. The article of claim 3 in which the stabilizing agent 6. The article of claim 3 in which the stabilizing agent 15 aniline hydrobromldeis aniline hydrochloride. No references cited. 

1. AN ARTICLE COMPOSED OF THE NAPPED FABRIC OF FIBERS OF SYNTHETIC LINEAR ACRYLONITRILE AND A STABILIZING AGENT SELECTED FROM THE GROUP CONSISTING OF ANILINE, ANILINE HYDROCHLORIDE, ANILINE SULFATE, ANILINE ACETATE AND ANILINE HYDROBROMIDE. 